The present invention relates to a digital signal recording method and a disk reproducing apparatus, and more particularly to such a method and an apparatus for recording a digital signal in the form of a data block on a disk adapted to be accessed by a host computer and for reproducing the digital signal from the disk.
A CD-ROM (CD-Read Only Memory) is a conventional example of this type of disk on which digital signals are recorded in units of a data block. Like the techniques described in Nikkei Byte, September 1994, p. 146, in the CD-ROM, data blocks composed of effective data and block addresses are recorded outward in order from the innermost track on the recording surface of the disk. When such a disk on which such data is recorded using the above technique is accessed and reproduced in accordance with a command from the host computer, a starting block address and a transfer block count are designated along with the access command, and desired data blocks are accessed and reproduced in accordance with such command and data.
Recently, disks each composed of two subdisks stuck to each other whose recording surfaces are readable from one side, disks having an upper recording surface and a lower recording surface whose recording surfaces are readable from one side, and disks each composed of two stuck-together sets of upper and lower recording surfaces which are readable from one side have been standardized. See, for example, the article "Confidence in Unique Standards of DVDs", Nikkei Sanqyo Shinbun, Feb. 24, 1995, and the article "Second Stage of Struggle for DVD Standards", Nihon Keizai Shinbun, Apr. 20, 1995.
When a digital signal is recorded using the above-mentioned technique on any of those disks having a plurality of recording surfaces, the host computer only recognizes the disks as having independent recording surfaces. In order to enable all of the recording surfaces to be accessed, the interface via which data is sent to and received from the host computer is required to be changed, and hence the conventional interface cannot be used as it is.
The above-mentioned technique has the problem that each time a recording surface to be reproduced is changed, it is necessary to read the innermost lead-in area before access and reproduction, such that it takes a long time to resume access and reproduction.